HP is positioning the machine squarely at corporate, enterprise customers. HP sells a lot of PCs to the enterprise, and some of those corporate buyers have expressed the interest in buying their smartphones from the company too to simplify procurement and support. Accordingly, it's heavily promoting the phone's security credentials: not only the dual biometrics, but FIPS 140-2 cryptography, 256-bit key full disk encryption, TPM 2.0, protection against firmware rollbacks, and so on.

Given Microsoft's strengths in the enterprise market—it has a lock on the corporate desktop, Windows Server is widely found in the server room, and its management tools such as Active Directory, System Center, and Intune are used to control hundreds of millions of machines—this corporate positioning makes some sense. The Universal Windows Platform provides a solid basis for building corporate line-of-business apps that'll run with only a little adaptation and modification on desktop systems, smartphones, and tablets, and Windows 10 Mobile fits neatly into the existing line-up of management tools.

Enlarge/ The back of the HP Elite x3 shows its Pogo pins, though it's still missing its fingerprint reader.

HP

Such advantages are a common feature of any Windows device, but the x3 goes a step further in a rather unusual way. In a lot of regards the Elite x3 is not just a smartphone; HP is building a device that could be the successor to all manner of weird and wonderful industrial devices using the old Windows Mobile. Far away from consumer markets, there were hundreds of handheld machines integrating things like credit card readers, barcode scanners, printers, and much more besides, all running Windows Mobile, typically with a resistive touchscreen and perhaps even a hardware keyboard.

HP has built the x3 to tap into this market, thanks to its most unusual feature: 5 Pogo pin contacts on the back. HP's ambition is that third parties will be able to build an array of sleeves that fit over the phone to give it the extra capabilities it needs to meet all these industrial needs. The Pogo pins will be exposed to applications on the phone so that line-of-business apps will be able to use the additional hardware contained within the sleeves. The sleeves will also be able to include extended batteries.

HP is also doubling down on Windows 10 Mobile's other big feature: Continuum, using the phone to drive a mouse, keyboard, and monitor, and run something resembling full desktop apps. To that end, the company is building two accessories for the x3. The first is the Desk Dock, which is very similar in purpose to the dock that Microsoft has for the Lumia 950 and 950 XL. The phone sits on the dock, connecting to it with its Type-C connector, and the dock sports a DisplayPort, two USB Type-A, one Type-C, and RJ-45 Ethernet ports. The design is arguably a little neater than Microsoft's dock, as the phone plugs directly into it rather than at the end of another cable, though the downside to this is that it makes using the phone while docked more awkward.

The second accessory is the Mobile Extender. It's basically a laptop without any working parts of its own. It contains a battery, a 1920×1080 12.5 inch screen, and a keyboard, but no intelligence. For that, it depends on the x3, connected over USB Type-C. This isn't the first time a company has tried to build a sort of "laptop dock" for a phone, but the high performance of the phone itself, combined with the fact that this is now a built-in capability of the operating system, thanks to Continuum, may give the idea some legs.

Pricing and availability are unknown. HP promises that it will be "competitive" but this is very much a high end device, so it's not going to be bargain basement. Availability is still some way off, with the company talking vaguely of "summer." One hint that it is still some way off is the fingerprint reader: although HP promises that it will have a fingerprint reader, the prototype hardware that we were briefly shown a week ago didn't actually include it.

Whenever it lands, we wouldn't expect to see it in too many stores, either. HP is assuming that it will sell directly to its enterprise customers, so availability at your local Best Buy or AT&T store may not materialize. Online sales will be available for those who want to grab one, and there's a chance they'll be found in Microsoft stores too.

The device is likely to be exclusively a GSM/UMTS/HSPA/LTE/LTE-A handset, too, with no CDMA/EVDO support. This represents a similar challenge to that faced by the Lumia 950. The x3 is unambiguously an enterprise-oriented device, but Verizon is estimated to have about 50 percent of that market. Verizon's non-LTE network requires CDMA/EVDO support, and thus far, the company has shied away from offering LTE-only devices.

There are CDMA carriers that have made this transition; au/KDDI in Japan is selling a number of LTE-only handsets for use on its network. These handsets use VoLTE for voice communication, and have no ability to fall back to CDMA/EVDO 2G/3G services. Sooner or later Verizon will support the same: pure LTE handsets with no legacy 2G/3G fallback. There was talk that the HTC One A9 might be the first phone offered in this way on Verizon, but that has now gone very quiet; HTC is still saying that this will happen via a software unlock some time this year, but there's no concrete information on when that might happen. When Verizon does officially open up to CDMA-less LTE-only devices then the HP Elite x3 will be able to come along for the ride.

The Elite x3 is an uncompromising device. It's not the first device aimed at "the enterprise," but it's doing so in a rather different way that that of, for example, BlackBerry. While manageability is one aspect of the value proposition, the scope for novel hardware integration using sleeves and the Pogo pins, and the emphasis on Continuum, make it something a little different. It's encouraging to see a company building so heavily on Windows 10 Mobile's unique features, and offering a specification that gives up little or nothing compared to the competitors—presuming HP can release the thing in a timely way, it'll be among the first wave of Snapdragon 820 devices to hit the market. Windows Phone never approached the cutting edge in quite this way.